Source Code 1992 March/Source_Code_CD-ROM_Walnut_Creek_March_1992.iso/usenet/altsrcs/2/2094/LASERFONTS

Text File | 1990-12-28 | 7KB | 168 lines

    How to build Fonts and Width Tables for your Laserjet
            2.1 90/07/18

This readme presents a general discussion on how to build fonts
for psroff.  The first part gives a complete description of what
needs to be done/how it's done, and you can skip to the second
part "AUTOMATING THE WHOLE DURN THING" if you want to use my facilities
for doing all this stuff without really needing to understand what's
happening.

Psroff has been designed to work with HP SFP or TeX PK format files.
Most fonts are called "normal" (Eg: R, I, B, etc.) which means that
they have ROMAN8 encodings.  Thus, HP SFP ROMAN8 SFP fonts can be
used as-is for psroff normal fonts (aside from copying them from
floppy, giving them the right names, building width tables).
On the other hand, the troff "S" font is a special font that I
supply which has (nominally) MATH8 encodings.

Knuth's TeX PK fonts cannot be used "out-of-the-box" because the
character encodings are different, and the characters that psroff
needs are scattered across many different fonts.

Do not despair, all is not lost - you can run psroff *purely* with
TeX fonts, with the help of a little pk2* magic.  The supplied
S font is an example of the result of this, and the S fonts contain
a few characters you'll need if you wish to build your own fonts.

In the subdirectory utils, there are several important tools:

    1) pk2sfp - which converts PK's and SFP's into SFP's,
       merging multiple ones and possibly with encoding changes.
    2) pk2ditwid - which reads a font file and generates
       font width information.
    3) maps/* - encoding files for converting from PK encoding
       to ROMAN8/MATH8 encodings.
    4) fonts/* - sample fonts.

(The following discussion assumes that you've built and installed
psroff).

First, examine utils/Makefile entry "buildcmtrf".  If you run this,
the Makefile will create several cmtrf*.sfp files under the fonts
subdirectory.  These cmtrf files are a subset of Rick Richardson's
"cmtrf" font which contains characters not in TeX's PK files that you
will need to build fonts for psroff.  Rick has graciously permitted
distribution of the cmtrf font with psroff, and I've placed the characters
in the distributed S font.  Buildcmtrf uses the "-m" option of pk2sfp
(see the manual page) to extract characters named in maps/S.cmtrf
("S-font-to-CMTRF") and produce cmtrf<pointsize>.sfp files.

Next, examine utils/Makefile entry "testmerge".  What this does is
run "pk2sfp -m" to generate several different fonts at the 10 point
size.  "testmerge" also invokes sfp2pk (if you have it - it comes
with Rick's jetroff package) to convert the resultant SFP to PK format.
Each font created by testmerge is a combination of several different
PK fonts.  The invocations of "pk2sfp -m" consist of something like:

    pk2sfp -m <mapfile> <fontfile> <mapfile> <fontfile>....

Where each map file contains a description of what character in the
following fontfile is needed and what encoding should be used.  The
naming convention of these map files is:

    <from>.<to>

Where "from" is usually a PK font name (eg: "cmtrf") and "to" is usually
either ROMAN8 (for normal fonts) or MATH8 (for symbol fonts).

This is how the 10 point R font was built:
    ./pk2sfp -m -v \
        maps/cmr.ROMAN8 \
        fonts/cmr10.pk \
        maps/cmsy.ROMAN8 \
        fonts/cmsy10.pk \
        maps/cmtrf.ROMAN8 \
        fonts/cmtrf10.sfp \
        maps/cmti.ROMAN8 \
        fonts/cmti10.pk \
        > fonts/R.10.sfp 2> fonts/R.10.LOG

A combination of cmr, cmsy, cmtrf, cmti.

NOTE: psroff will work equally well with SFP's and PK's.  There is
a substantial space advantage to converting SFP's to PK's (if you have
sfp2pk), but it is *not* necessary.  Further, you can always compress
your SFP's in place, and psroff will automatically invoke compress
when it needs to read them.  It's only important that you get the
naming convention correct (<troffname>.<pointsize>.<pk|sfp>) and
the lj.fonts file set correctly.

So, the testmerge entry of the utils/Makefile creates R, I, B, C, S,
H, etc fonts at 10 points.  Only 10 points.  You could operate
with these only - but you'd only have one size.  Yuck.  (I distribute
R, I, and B only at 10 points so that you can see that psroff actually
works and not get discouraged before trying to obtain more fonts).

This is where it gets interesting.  TeX fonts usually come (as in the
U of T distribution) in the following naming format:

    <TeX Name><designsize>.<resolution>pk

Eg: cmr10.329pk.  What this means that if the characters were printed
on a device with a resolution of 329 dots/inch, the characters would
be 10 points high.  However, the Laserjet is 300 DPI, right?  If you
were to print the font at 300 DPI, the characters would appear to
be (329/300 * 10) points = 10.996... points (11 with a small error),
wouldn't they?  Thus, you could use cmr10.329pk to generate a 11 point
font.

[NOTE: if the resolution is omitted, it is assumed to be 300 DPI -
as in the utils/fonts subdirectory]

By finding cmti and cmsy (cmtrf11.sfp was built by buildcmtrf
remember?) in the same fashion where the design size and DPI are *close*
to 11, you can build the R font at 11 points simply by substituting
the "fonts/*" names in the pk2sfp -m command line with the appropriate
font names (the map files don't change).  Thus, you can build R, I, B
in several different point sizes.  Note: sometimes you can't find
a TeX font with a DPI/pointsize close enough to the desired point size.
The S fonts were built with a maximum error of approximately 7%.

AUTOMATING THE WHOLE DURN THING:

There is a perl script in utils called "calcfonts", which if invoked
in the top level make via:

    make buildljfonts

Will traverse every directory you've specified for PKFONTS during
configuration of the top-level-makefile, select the best fit for
each font size, and build as many psroff font files as it can, placing
each font in $NEWFONTS.  Preferably you should have a sfp2pk utility
(so that the fonts can be created as pk's - specify in the Makefile),
but if you don't SFP's will be generated.  $NEWFONTS/lj.fonts.new
will contain some new replacement entries for your lj.fonts file (make
sure that the order is R, I, B and S).

After running buildljfonts, issue:

    su root
    make installljfonts
    ^D
    make register
    su root
    make installwidths

The first make will install all of the new laserjet fonts in utils/newfonts.
The second builds the width tables all over again, and the third reinstalls
the width tables.

calcfonts can be user-modified to emit more fonts.  Near the end there
are "do gen" invocations, eg:

    do gen("troffname", "English name", "HPLJ escape sequence", "set",
    "pkname", "pkname", ....);

Troffname is the name that the font will be known by to psroff/troff.
English name and HPLJ escape sequence are for the lj.fonts file.
Each "pkname" is the name of a PK format file used to generate part of
the font, and will be MERGED with the map file called "pkname.set".
"set" should always be ROMAN8 (except for building S fonts when it
should be MATH8).  If the pkname contains a slash (eg: cmr/foo), it
means merge cmr PK's using the second token as the map name.  Eg:
"cmr/foo" means merge cmr's using "foo.set".  The escape sequence is
only used if you've selected a point size which is marked "b" (builtin),
or is marked "n" (non-existent), and the bestmatch code in lj.c didn't
find an existing font (same typeface) at a "close enough" pointsize.